The tissue-specific differentiation potential of airway normal epithelial cells. (a) Matrigel 3D cultures of HNTEC. HNTEC and A549 cells were cultured in 5% Matrigel for 7 days. Matrigel 3D cultures were stained with 0.5 μg/ml DAPI and analyzed with fluorescence microscopy. Scale bar, 200 μm. (b) Histology comparison of the original tracheal tissues and 3D ALI culture of HNTEC. HNTEC were cultured in 3D ALI for 19 days. Magnification 40x. (c) Expression of mucin 5AC in HNTEC-derived ALI 3D culture. 3D ALI cultures were fixed, permeabilized, and labeled with the primary antibody against mucin 5AC. The expression of mucin 5AC was measured by immunofluorescence protocols. The cellular nuclei were stained with 0.5 μg/ml DAPI. Magnification 40x.